UV Index in Knoxville, United States

Last updated: June 2, 2025

In Knoxville, United States, understanding the UV Index is essential for maintaining skin health and preventing sunburn. With the humid subtropical climate (Cfa), residents and visitors alike often encounter heightened UV exposure, especially during the peak hours from 10 AM to 2 PM when values can soar to 11. By being aware of the UV Index, you can make informed decisions about sun protection to safeguard your skin against harmful impacts. Knowing when the UV levels are high allows you to enjoy the sunny Knoxville outdoors while minimizing the risks associated with solar radiation.

Hourly UV Index in Knoxville

The UV Index for today shows a dramatic rise as the sun ascends into the sky. Starting at a mild 1 by 07:00, the index gradually builds, reaching 3 by 09:00 and peaking at an intense 11 at 13:00—a level where sun protection is crucial. From this pinnacle, the values start to decline, tapering off to 10 at 14:00 and then gradually decreasing through the afternoon and evening, with values of 6 at 16:00 and sliding down to 1 by 19:00. Plan your outdoor activities accordingly, and remember to protect your skin during those peak hours!

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
Time	UVI	Category	Time to Burn
07:00	1	low	45 min
08:00	2	low	45 min
09:00	3	moderate	30 min
10:00	6	high	25 min
11:00	8	very high	15 min
12:00	10	very high	15 min
13:00	11	extreme	10 min
14:00	10	very high	15 min
15:00	9	very high	15 min
16:00	6	high	25 min
17:00	4	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Knoxville

Throughout the year, the UV Index experiences significant seasonal fluctuations, with the highest levels occurring during the summer months. Notably, from May to August, the UV Index reaches extreme levels of 11, indicating a high risk for skin damage with a burn time of only 10 minutes. In contrast, the winter months, especially January and December, see moderate UV levels of 4, allowing for a safer exposure time of 30 minutes. The months of February and March also present heightened risks with UV indices of 6 and 8, respectively, highlighting the necessity for caution as spring approaches. Residents and visitors are advised to protect their skin during April to September when the UV values are particularly elevated. Measures such as wearing sunscreen, protective clothing, and seeking shade during peak sun hours are strongly recommended to reduce the risk of sunburn and long-term skin damage.

Monthly Maximum UV Index for Knoxville, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Knoxville. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.

Data source: Statistical UV Index data for Knoxville, based on information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

Compare Knoxville UV Index with Other United States Cities

The table above highlights how UV exposure in Knoxville compares to other major locations across United States. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.

Knoxville's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Chicago UVI	3	4	6	8	9	10	10	9	8	6	4	2
Brooklyn UVI	3	5	6	8	10	10	9	9	8	6	4	2
New York City UVI	3	5	6	8	10	10	9	9	8	6	4	2
Los Angeles UVI	4	6	8	9	10	11	11	10	10	7	5	4
Knoxville	4	6	8	10	11	11	11	10	9	7	5	4
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5